1. Field of the Invention
The present invention relates to a power-driven striking tool, such as a power-driven hammer or a power-driven hammer drill. More specifically, the invention pertains to a power-driven striking tool with a striking member, which connects with a piston reciprocating in a housing and strikes a bit attached to an end of the housing directly or indirectly via an intermediate element interposed between the striking member and the bit.
2. Description of the Related Art
Power-driven striking tools may be provided with a mechanism for preventing idling strikes as disclosed in JAPANESE PATENT LAYING-OPEN GAZETTE No. 1-240278. According to this mechanism, while the tool is operated idly, with the bit not in contact with the ground or some other work surface, the striking member is gripped by a gripping member when thrust in the forward position, so that the striking member is no longer interlocked with the piston. A cushioning material provided in front of the intermediate element cushions the impact of the intermediate element thrust forward by the first idling strike and prevents the intermediate element from recoiling and dislodging the striking member from the gripping member. Furthermore the mechanism has another cushioning material provided behind the intermediate element for reducing the recoil of the bit transmitted to the main body of the tool in normal operation.
In the prior art described above, the functions of gripping the striking member for preventing idling strikes, braking the thrusting intermediate element, and reducing the recoil of the bit in normal operation are performed in different locations, such as between the striking member and the intermediate element and in front of the intermediate element. Consequently, a number of additional parts are required for these functions, resulting in a more complex structure and increased manufacturing process and cost. The same is true of the type of tools without an intermediate element; such a tool also requires a gripping member for gripping the striking members as well as a separate cushioning material for preventing recoil of the bit.